Many special purpose wrenches are known for removing cylindrical oil filters. Most of these employ a rigid metal band which conforms to the outer circumference of the filter. As pressure is applied to the handle, the band tightens around the filter and imparts a force which twists the filter for removal. Since the metal band is smooth, it often tends to slide around the filter rather than twist it. When additional pressure or force is applied, the band often tends to bend the filter out of shape, thus ruining the filter and making that wrench useless for removing the filter.
Thus, flexible straps were substituted for the metal band in an attempt to improve the performance of the wrench (See, e.g., U.S. Pat. Nos. 3,728,916, 3,962,936, 4,249,245, 4,345,494 and 4,860,617). Since the strap would tend to stretch much more than metal, these wrenches would be ineffective unless some mechanism is provided to compensate for the greater amount of stretch of the flexible strap.
Current adjustable flexible strap wrenches are often in need of other tools for proper usage, causing more expense to the consumer. Others are complicated and take up space in small areas, such as engine compartments, where room is limited. The devices of U.S. Pat. Nos. 4,221,140, 4,506,568 and 4,646,593 need additional tools for proper usage, thus producing a more complicated and expensive tool. In addition, these wrenches do not apply the torque quickly and directly to the object, because the strap must rotate at least partially around a shaft before tightening, which often causes slippage. U.S. Pat. No. 4,848,192 requires a relatively larger space to apply the wrench to the filter because the lever is offset from the strap. Thus, the user must pull the strap back and then apply force to the lever to lock the strap in place. This must be done before pressure can be applied to remove the filter. After extended use, the handle can cut the strap and require replacement.
The present invention provides a simpler, more durable, more effective tool that is relatively inexpensive, takes up a small amount of space in a tool box, and does not require other objects for use.